1. Field of the Invention
The invention refers to a correction device for an optical arrangement that exhibits a light path, for example for a microscope. It specially refers to a confocal microscope with such a correction device.
2. Related Art
Optical arrangements, like for example microscopes, confocal microscopes or laser scanning microscopes regularly exhibit adjustable elements, in order to adjust different operating conditions. Thus it is well known for example, to exchange filters or color splitters, in order to be able to work with different lighting wavelengths or to evaluate different fluorescence radiation in different wavelength ranges. The adjustment or change mechanisms must be implemented regularly, mechanically and very expensively and with high precision, in order to keep the chances of unwanted disturbances of the light path during element change or element adjustment as small as possible.
This problem is faced especially in confocal microscopes or laser scanning microscopes, in which a confocal slit with a detector unit is used, that either contains a detector screen on its side or acts as one. Since even with very large mechanical expenditure for the changeable or adjustable elements, influences of the light path for example by tipping errors or wedge errors at the optical element can never be completely ruled out, partially cost-effective correction mechanisms are provided in the prior art, to change the light path of the image with such pinhole-objectives.
Thus in DE 101 47 481 A1 for example an adjustable confocal slit for a laser scanning microscope is described, that makes a displacement of the aperture possible, to be able to shift the confocal slit appropriately in tipping errors or wedge errors that are caused by adjustment or change of optical elements, so that an optimal image is always formed in the confocal microscope. The DE 101 07 210 C1 describes a similar approach, which likewise adjusts relevant elements in the optical arrangement. There, in a confocal microscope a focusing lens in the arrangement can be shifted transverse to the Z-axis of the light path. It can also be used to bring about an adjustment of the image in the confocal microscope.
It is thus common in the approaches of the prior art, to change the optical arrangements in the confocal microscope, i.e. in the optical imaging arrangement—either by the change of the location of a confocal slit with respect to the object to be imaged or by the adjustment of other imaging elements of the imaging optics. Apart from a relatively large mechanical/optical effort necessary in these approaches, there exists a fundamental problem in this principle pursued in the state of the art, that the reproduction ratios are no longer comparable from time to time. A laborious new calibration of imaging scales can become necessary.